Polyester-Polysiloxane Hyperbranched Block Polymers for Transparent Flexible Materials

Highly transparent flexible silicone elastomers are useful for certain stretchable electronics and various types of smart devices. Polyester-polysiloxane hyperbranched block copolymers are synthesized by ring-opening polymerization of octamethylcyclotetrasiloxane initiated by macromolecular lithium alkoxide. Treatment of these copolymers with tetraethoxysilane and dibutylin dilaurate at room temperature gives the corresponding transparent elastic materials. The transparency of the materials can reach 90% (700-800 nm), and the starting thermal decomposition temperatures of the materials are higher than 330 °C. Very interestingly, though the highest tensile strength of the material prepared is about 0.48 MPa, the elongation at break can reach 778-815%. The results will inspire us to develop highly transparent flexible silicone materials by designing copolymers of silicone materials and hyperbranched polymers.